The primary objectives of this trial are to:

* Characterize the safety and tolerability of TEV-56278
* Determine the Recommended Phase 2 Dose (RP2D)
* Evaluate antitumor activity of TEV-56278 (Part 2 only)
* Determine the safety and tolerability of TEV-56278 in combination with pembrolizumab
* Determine a RP2D of TEV-56278 in combination with pembrolizumab

The secondary objectives of this trial are to:

* Characterize the serum pharmacokinetics of TEV-56278
* Evaluate the antitumor activity of TEV-56278
* Determine the safety and tolerability of TEV-56278
* Evaluate other measures of antitumor activity of TEV-56278
* Evaluate anti-tumor activity

Participants will be treated up to 12 months with a follow-up period of up to 12 months after last infusion. The total duration of the trial will be up to 25 months for individual participants.

Participants who exhibit a favorable benefit risk profile at the end of the 12 month trial treatment period may be offered an opportunity for an extended treatment period in which they can be treated for a maximum of 12 additional months (up to 26 additional cycles of TEV-56278).